A crystalline thermoplastic resin, such as polyamide, polyester and polyphenylene sulfide has several drawbacks including significant deformation in molding and insufficient heat resistance while possessing excellent mechanical properties, flow properties and oil resistance.
A non-crystalline thermoplastic resin is often blended with a crystalline thermoplastic resin to improve these drawbacks of the crystalline thermoplastic resin. A polyphenylene ether resin, which is a non-crystalline thermoplastic resin having high heat resistance, is especially appropriate to be blended with the crystalline thermoplastic resin.
A number of blended resin compositions of a crystalline thermoplastic resin and a polyphenylene ether resin have been proposed; for example, a resin composition of polyphenylene ether and polyamide disclosed in JAPANESE PATENT LAYING-OPEN GAZETTE No. Sho-56-16525. a resin composition of polyphenylene ether and polyphenylene sulfide in JAPANESE PATENT PUBLICATION GAZETTE No. Sho-56-34032, a resin composition of polyphenylene ether and polyester in JAPANESE PATENT LAYING-OPEN GAZETTE No. Sho-49-50050. and a resin composition of polyphenylene ether and polyolefin in JAPANESE PATENT LAYING-OPEN GAZETTE No. Sho-58-103557.
Such blended resin compositions have poorer flow properties than those of the compositions non-blended crystalline thermoplastic resin though the polyphenylene ether resin has compensated some of the above drawbacks that the crystalline thermoplastic resin has. Further blending of a low molecular compound for improvement in flow properties generally lowers the heat resistance and deteriorates the mechanical properties of a resultant resin composition.